UNIVERSITY   OF    CALIFORNIA 

COLLEGE  OF    AGRICULTURE 

AGRICULTURAL   EXPERIMENT   STATION 

BERKELEY,    CALIFORNIA 

CIRCULAR  263 

Revised  May,  1928 

TOMATO  PRODUCTION  IN  CALIFORNIA 

J.  T.  ROSAi 


Tomato  growing  is  one  of  the  important  agricultural  industries 
of  California.  In  1927,  4,491  carloads  of  tomatoes  were  shipped  for 
table  purposes;  the  canneries  packed  2,256,878  cases  of  the  whole 
tomato,  and  2,166,000  cases  of  other  tomato  products,  such  as  pulp, 
puree,  catsup,  and  paste.  Shipments  of  table  stock  constituted  14 
per  cent  of  the  total  for  the  entire  United  States,  and  the  California- 
canned  product  was  17.2  per  cent  of  the  national  total.  Acreage  and 
production  fluctuate  from  year  to  year,  but  the  tendency  is  for  a 
steady  increase,  especially  in  the  shipments  of  tomatoes  for  use  in  the 
fresh  condition.  Large  quantities  are  grown  for  local  markets ;  a  con- 
siderable acreage  is  grown  especially  for  seed  production;  and  in 
home  gardens  everywhere  the  tomato  is  a  crop  of  first  importance. 
Thus  it  is  seen  that  the  tomato  is  grown  for  a  number  of  distinct 
purposes  in  the  state,  each  of  which  is  of  considerable  importance. 

The  average  yield  in  California  has  varied  from  5.5  to  7.2  tons  to 
the  acre  in  recent  years.  While  these  yields  are  much  above  the 
average  for  the  whole  United  States,  greater  yields  are  attainable 
with  the  favorable  soil  and  climatic  conditions  existing  in  many  sec- 
tions of  California,  Yields  of  10  to  25  tons  per  acre  are  frequently 
obtained  by  skillful  growers.  Surveys  in  other  states  have  shown  that 
the  grower  whose  yield  is  below  the  average  is  likely  to  be  losing 
money  on  the  crop,  while  other  growers  in  the  same  district  whose 
yields  are  above  the  average,  make  a  profit.  The  object  of  this  circular 
is  to  describe  methods  of  growing  and  handling  tomatoes,  and  to  point 
out  in  a  general  way  some  of  the  principles  underlying  better  pro- 
duction. However,  when  the  culture  of  such  a  crop  as  tomatoes  is 
considered,  due  allowances  must  always  be  made  for  the  diversity  in 
soil  and  climatic  conditions  existing  within  the  state,  and  the  variety 
of  purposes  for  which  the  crop  is  grown. 

i  Assistant  Professor  of  Truck  Crops  and  Associate  Plant  Breeder  in  the 
Experiment  Station. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


TOMATO   PRODUCING    DISTRICTS 

Commercial  production  is  more  or  less  centered  in  a  number  of 
important  districts,  each  of  which  usually  specializes  on  the  growing 
of  a  certain  type  of  tomato  for  one  particular  use.  The  earliest 
tomatoes  are  grown  in  the  Imperial  Valley.  Only  market  tomatoes 
are  grown  in  this  section  and  they  are  shipped  extensively  to  cities 
west  of  the  Mississippi.  About  1,000  acres  are  grown  annually,  the 
planting  being  in  November  and  December,  and  the  shipping  season 
extending  from  early  May  until  July.  Possibly  the  use  of  a  better 
shipping  variety,  or  the  adoption  of  better  cultural  practices,  may 
result  in  the  production  of  fruit  that  can  be  marketed  successfully 
further  east,  in  competition  with  the  Florida  crop. 

Los  Angeles,  Ventura,  Riverside,  Orange,  and  San  Diego  counties 
produce  a  large  quantity  of  tomatoes  for  canning,  but  most  important 
in  this  district  is  the  production  of  a  late  or  fall  crop  for  eastern 
shipment.  Prom  September  to  December,  after  disease  has  killed  the 
plants  in  the  southern  states  and  frost  has  ended  the  crop  in  the 
north,  there  is  a  good  demand  for  California  tomatoes.  Frost  usually 
kills  the  plants  in  November  in  the  southern  coastal  counties  of  Cali- 
fornia, but  in  San  Diego  and  in  frost-free  areas  elsewhere,  shipping 
may  continue  to  January  first.  For  the  fall  crop,  seed  is  planted  in 
open  beds  in  April,  and  transplanted  to  the  field  in  June  and  July. 

The  lower  San  Joaquin  Valley  produces  a  considerable  quantity 
of  tomatoes,  most  important  being  the  culture  of  early  varieties  for 
shipment,  at  Merced.  After  the  shipping  season  ends,  the  latter  part 
of  the  crop  is  utilized  for  manufacturing  purposes.  Tomato  produc- 
tion in  this  section  is  on  an  extremely  intensive  basis  and  the  returns 
by  the  acre  are  high.  Canning  of  tomatoes  is  also  important  in 
Stanislaus  and  San  Joaquin  counties.  The  seed  is  sown  in  hotbeds  just 
after  Christmas,  and  the  plants  are  set  in  the  field  about  March  1, 
for  the  early  market  crop,  while  the  canning  crop  in  this  district  is 
planted  somewhat  later. 

The  Santa  Clara  Valley  is  one  of  the  oldest  and  most  important 
districts  for  the  production  of  tomatoes  for  canning  and  manufac- 
turing. In  this  district,  as  in  the  ones  following,  the  sowing  is  done 
in  hotbeds  early  in  January,  the  seedlings  are  transplanted  to  cold- 
frames,  and  thence  to  the  field,  during  May. 

The  San  Francisco  Bay  district,  including  the  Peninsula  and 
Alameda  County,  is  an  important  center  for  the  production  of  canning 
and  manufacturing  stock,  as  well  as  fruit  for  local  markets  and  for 


CiRC.  263]  TOMATO   PRODUCTION   IN    CALIFORNIA  3 

shipments  to  the  East  during  the  fall  months.  Some  growers  contract 
their  entire  crop  to  a  cannery,  while  others  ship  their  crop  when 
market  conditions  provide  a  profitable  outlet,  or  when  the  shipping 
market  is  not  good  send  their  crop  or  a  portion  of  it  to  the  canneries. 

The  Sacramento  Valley  has  several  districts  which  produce  canning 
tomatoes  extensively.  One  of  the  most  important  of  these  is  around 
Sacramento. 

Sonoma.  County  is  an  important  district  for  cannery  production. 
On  account  of  the  cool  climate,  relatively  early -maturing  varieties  give 
a  larger  yield  of  ripe  fruit  in  this  region  than  the  usual  canning 
varieties. 

There  are  many  other  localities  where  the  crop  is  grown  for 
canning  and  other  purposes  on  a  smaller  scale.  Production  for  local 
markets  is  more  or  less  important  in  all  parts  of  the  state.  Fifty-two 
counties  in  California  report  a  commercial  tomato  acreage. 


LOCATIONS    FOR   TOMATO    GROWING 

Before  engaging  in  extensive  tomato  production,  the  grower  must 
make  sure  that  there  is  a  profitable  outlet  for  his  crop ;  that  is,  he 
must  have  access  to  a  good  local  market,  to  a  cannery  or  other  manu- 
facturing plant,  or  be  so  situated  that  he  can  ship  to  advantage.  It 
is  generally  not  advisable  to  grow  the  crop  for  shipment  unless  the 
acreage  is  large  enough  to  make  carload  lots  possible,  either  by  the 
individual  grower  or  by  groups  or  associations  of  smaller  growers 
located  in  the  same  community.  The  season  at  which  the  crop  will 
mature  and  the  probable  market  conditions  existing  at  that  time 
should  be  carefully  considered. 

The  tomato  is  a  heat-loving  plant  and  the  long  growing  season  in 
most  parts  of  the  state  is  very  favorable  for  tomato  production. 
Localities  subject  to  late  spring  or  early  fall  frosts,  or  with  very  cool 
summer  climate,  are  not  suitable  for  the  crop. 

As  to  type  of  soil,  the  tomato  is  not  particular,  though  this  factor 
may  influence  yield,  quality,  and  time  of  maturity  to  some  extent. 
Sandy  soils  favor  an  early  maturing  crop,  while  heavier  soils  are 
especially  suited  for  late  maturing  or  fall  crops.  Muck  or  peat  soils, 
though  usually  considered  unsuited  to  tomatoes,  have  been  observed 
to  produce  excellent  crops  of  good  quality  when  the  moisture  supply 
was  not  excessive  (fig.  1).  Good  drainage  is  always  essential.  Soils 
that  are  too  moist  for  any  considerable  period  during  the  growing 
season  usually  produce  a  poor  crop,  because  of  excessive  vine  growth 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

and  a  poor  set  of  fruit.  Soils  that  are  excessively  rich  in  nitrogenous 
matter  may  produce  a  similar  effect.  Other  crops  than  the  tomato 
may  make  more  profitable  use  of  the  fertility  provided  by  plowing 
under  an  alfalfa  sod.  The  tomato  will  root  deeply  unless  prevented 
from  it  by  plow  sole,  hardpan  or  poor  drainage.  The  history  of  the 
land  from  the  standpoint  of  alkali  content,  and  nematode-  and  wilt- 
infection,  is  also  important,  for  the  tomato  is  very  susceptible  to 
injury  by  these  things. 


Fig.  1. — Tomatoes  as  an  intercrop  in  an  asparagus  plantation,  the  first  year. 
This  was  on  well-drained  peat  soil  at  Terminus,  California.  The  tomatoes  were 
of  good  quality. 


CROPPING   SYSTEM 

A  large  part  of  the  tomato  crop  in  northern  and  central  California 
is  produced  in  rotation  with  a  winter  crop  of  spinach.  The  tomato 
plants  are  pulled  and  burned  after  picking  is  finished  in  November ; 
the  land  is  fitted  and  sown  to  spinach  at  once.  The  spinach  crop  is 
harvested  in  March  and  April,  and  the  land  is  prepared  for  tomatoes 
again,  the  plants  being  transplanted  during  May.  This  combination 
is  a  good  one,  but  may  lead  to  bad  results  if  the  same  land  is  con- 
tinuously cropped  in  this  way.  Tomatoes  should  not  be  grown  more 
than  once  in  four  years  on  the  same  piece  of  land;  they  should  be 
grown  in  rotation  with  other  crops.  Certain  diseases  and  insects  often 
become  prevalent  and  do  much  damage  when  tomatoes  are  grown 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


continuously.  The  double-cropping  of  land  with  winter  vegetables 
and  tomatoes  is  practicable  only  when  the  tomato  crop  can  be  irrigated. 
That  tomatoes  exert  an  injurious  or  poisonous  effect  upon  subse- 
quent crops,  is  an  idea  held  by  some  growers,  but  which  is  not  founded 
upon  fact.  When  the  dead  tomato  vines  are  plowed  under,  they  have 
a  beneficial  effect.  However,  when  they  are  piled  and  burned,  the 
accumulation  of  ash  in  these  spots  may  be  injurious  to  the  next  crop. 


Fig.  2. — Tomatoes  as  an  intercrop  in  a  three-year-old  peach  orchard  at 
Merced.  Though  the  trees  are  24  feet  apart,  there  is  room  for  only  two  rows 
of  tomatoes.  Competition  for  water  between  trees  and  tomatoes  will  be  severe, 
requiring  heavy  irrigation.  The  shade  of  the  trees  reduced  loss  from  yellows 
disease  in  the  tomatoes. 

Tomatoes  are  extensively  grown  as  an  intercrop  in  young  orchards 
(fig.  2),  to  which  purpose  they  are  well  adapted  when  the  irrigation 
practice  for  tomatoes  does  not  conflict  with  the  requirements  of  the 
trees.  This  may  sometimes  be  an  objection,  especially  in  young  walnut 
groves.  Deciduous  fruit  orchards  should  not  be  intercropped  with 
tomatoes  after  the  third  year. 


VARIETIES 


The  choice  of  a  suitable  variety  of  tomato  depends  upon  the  use 
for  which  the  crop  is  intended,  the  climate  of  the  locality,  the  season 
of  year  at  which  it  is  to  be  marketed,  and  the  presence  or  absence  of 
certain  diseases  to  which   the  variety  may  be   susceptible.      Many 


b  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

varieties  have  been  developed  which  are  early  in  maturing,  but  they 
may  or  may  not  be  suitable  for  shipping,  and  are  generally  too  small 
to  be  suitable  for  canning.  Other  varieties  are  too  large  or  too  rough 
for  fresh-fruit  markets,  but  have  qualities  which  make  them  suitable 
for  manufacturing  purposes.  To  get  high  quality  seed  of  a  variety 
adapted  to  local  conditions  and  uses,  is  important.  The  cost  of  good 
seed  is  only  a  small  item,  for  one  pound  will  produce  enough  plants 
for  25  acres  of  canning  tomatoes.  In  the  following  list  is  described 
a  limited  number  of  varieties,  which  have  been  found  satisfactory  for 
one  or  more  purposes  in  California. 

Earliana. — Several  rather  distinct  improved  strains  of  this  variety 
are  now  available,  such  as  North  Dakota  Earliana,  Morse's  Special 
Early,  Alacrity,  Burbank,  King  of  the  Earlies,  and  others.  The 
original  Earliana  was  a  flat,  rather  rough  tomato,  but  the  improved 
strains  just  mentioned  produce  mostly  smooth,  globular  fruit.  The 
plants  of  Earliana  are  comparatively  small  and  weak-growing,  requir- 
ing only  one-third  as  much  space  to  the  plant  as  late  varieties.  The 
fruit  is  red,  early  in  maturing,  but  small  compared  with  late  varieties. 
Earliana  is  an  excellent  variety  for  extra-early  crop  for  growers  cater- 
ing to  a  local  market.  It  is  also  used  to  some  extent  for  spring 
shipments. 

Globe. — The  fruit  is  purple,  round  to  slightly  elongated  in  shape, 
somewhat  larger  than  Earliana,  and  is  about  two  weeks  later  in  ripen- 
ing. Globe  has  long  been  the  standard  shipping  variety  of  Florida 
and  the  Gulf  States,  but  is  little  used  in  California. 

Mar  globe. — This  variety  was  introduced  a  few  years  ago  by  F.  S. 
Pritchard  of  the  United  States  Department  of  Agriculture.  It  was 
the  result  of  hybridizing  the  Marvel  and  Globe  varieties,  followed  by 
selection  for  the  Fusarium  wilt  resisting  quality  of  Marvel,  and  the 
shipping  quality  of  Globe,  which  characters  it  combines  to  a  satis- 
factory degree.  In  addition,  it  possesses  considerable  resistance  to  nail- 
head  spot  (Alternaria),  a  serious  disease  in  some  sections  outside  of 
California.  Largely  for  this  reason,  Marglobe  is  being  used  extensively 
in  the  southern  states  and  in  Mexico.  The  fruit  is  round,  red,  of 
medium  size,  of  good  shipping  quality,  and  medium  early.  It  has 
proven  satisfactory  in  Imperial  Valley,  and  in  southern  California 
for  fall  shipping. 

Stone. — This  variety  is  usually  classed  as  "late,"  the  fruit  ripen- 
ing nearly  a  month  after  Earliana,  but  about  two  weeks  earlier  than 
San  Jose  Canner  and  related  canning  varieties.  The  plants  are  like- 
wise intermediate  in  size,  between  that  of  the  foregoing  varieties.    The 


Circ  263] 


TOMATO   PRODUCTION   IN    CALIFORNIA 


Fig.  3. — Fruit  of  the  Stone  or  Norton  variety,  showing  the  smoothness  at 
stems  and  blossom  ends,  and  freedom  from  blemishes.  (From  Agr.  Exp.  Sta. 
Circ.  280.) 


8  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

fruit  is  red,  slightly  flattened,  generally  smooth  and  free  from  "cat- 
faces,"  and  is  of  medium  to  large  size  (fig.  3).  Stone  is  much  used 
as  a  dual-purpose  variety,  for  late  shipping  and  for  canning,  in  the 
Los  Angeles  district.  It  is  also  a  fairly  satisfactory  variety  for  fall 
shipment  in  central  and  northern  California.  While  its  smoothness 
commends  it  to  the  canner  for  putting  up  a  "solid  pack,"  the  fruit 
of  this  variety  tends  to  be  too  small  for  economical  canning  crop 
production,  except  where  the  soil  is  very  fertile  and  moist,  or  where 
the  growing  season  is  too  short  or  too  cool  to  permit  of  growing  the 
larger  canning  varieties. 

Norton. — This  is  a  strain  of  the  Stone,  which  is  highly  resistant 
to  the  Fusarium-wilt  disease.  This  does  not  imply  resistance  to  other 
troubles.  It  was  introduced  by  F.  S.  Pritchard,  of  the  United  States 
Department  of  Agriculture,  in  1918.  That  Norton  is  wilt-resistant  has 
been  well  demonstrated  in  Los  Angeles,  Kiverside,  and  San  Diego 
counties,  and  as  it  is  in  all  other  respects  practically  identical  with 
Stone,  it  should  be  grown  wherever  a  variety  of  the  Stone  type  is 
desired. 

Morse's  Canner. — Although  originally  selected  for  canning  pur- 
poses, this  variety  is  now  more  important  for  the  late  market  crop. 
The  plants  and  the  fruit  in  general  resemble  Stone,  but  the  fruit  is 
considerably  larger,  and  is  generally  smooth,  red  in  color,  globular 
or  slightly  flattened.  This  variety  probably  produces  the  largest 
tomatoes  of  any  smooth  fruited  variety.  The  large  cells,  and  failure 
to  color  evenly,  are  said  to  be  its  main  defects  from  the  canner 's 
viewpoint. 

Italian  Stone  or  Qiiartinino. — These  names  are  usually  applied  to 
a  medium-early  variety,  grown  chiefly  in  the  Merced  district  and 
entirely  distinct  from  Stone.  When  not  pruned  to  a  single  stem,  the 
plants  assume  a  very  distinct  compact  semi-erect  type  of  growth. 
The  fruit  is  more  completely  protected  from  the  sun  by  the  dense 
foliage,  than  in  any  other  variety.  The  fruit  is  red,  flattened,  medium 
in  size,  inclined  to  be  rough  or  corrugated,  and  is  more  acid  than 
usual  in  flavor.  The  improved  strains  of  Earliana  have  been  found 
to  be  considerably  superior  to  it  in  earliness  and  in  production  of 
U.  S.  No.  1  grade  fruit. 

San  Jose  Canner. — This  name  is  generally  applied  to  a  large, 
rather  rough,  and  late  maturing  variety,  widely  used  for  the  canning 
crop  in  central  and  northern  California.  Santa  Rosa,  Diener,  San 
Felipe,  and  Jap  Canner  are  other  names  applied  to  this  variety,  or  to 
certain  growers'  strains  of  it.  Santa  Clara  Canner  is  an  improved 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


9 


strain  of  the  Canner  type,  developed  by  C.  C.  Morse  and  Company. 
Cal.  No.  1,  Cal.  No.  55,  Caleven,  and  Calpac  are  other  strains  intro- 
duced by  the  California  Agricultural  Experiment  Station,  and  are 
the  result  of  several  years'  selection  by  J.  W.  Lesley  and  J.  T.  Rosa, 
for  a  smoother,  more  uniform  type  than  the  original  variety. 

The  original  San  Jose  Canner  variety  was  probably  derived  from 
Trophy.  It  has  very  large  fruits,  much  flattened  in  shape,  and  many 
of  them  have  a  deep  corrugated  depression  at  the  stem  end  and  a  large 
irregular  scar  at  the  stylar  or  "blossom"  end  (fig.  5).  These  defects 
cause  a  high  percentage  of  waste  in  preparing  the  fruit  for  canning. 


Fig.  4. — This  shows  the  varying  degrees  of  roughness  and  corrugation  at  the 
stem  end  in  the  old  types  of  the  San  Jose  Canner  variety.  (From  Hilgardia, 
vol.  2,  no.  2.) 


However,  the  fruits  possess  a  high  degree  of  solidity  and  an  excellent 
color,  which  commend  them  strongly  for  canning.  Furthermore,  the 
large  size  of  fruit  and  the  heavy  yield,  makes  this  variety  an 
economical  one  to  grow  and  to  harvest.  The  improved  strains  (fig.  6) 
are  in  general  much  smoother  and  more  uniform  in  shape  than  the 
original  type,  while  retaining  the  large  size,  solidity,  and  color  of  the 
parent.  The  solidity  is  in  part  due  to  a  tough  epidermis,  in  part  to 
the  large  meaty  core,  and  the  numerous  small  cells  or  locules,  with 
thick  radial  walls.  Some  of  the  improved  strains  are  much  earlier  in 
maturing  than  others. 


10  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Trophy.  (Alameda  Trophy) . — The  variety  grown  under  this  name 
in  California  is  different  from  the  original  Trophy  variety.  It  is 
much  used  for  making  catsup  and  other  manufactured  products, 
especially  in  Alameda  County,  but  the  fruit  is  too  rough  to  permit 
of  canning  it  economically.  The  fruit  is  medium  to  large,  flattened, 
usually  very  rough  or  corrugated,  and  resembles  the  San  Jose  Canner 
in  internal  structure.  The  deep  red  color  of  the  pulp  is  partly  a 
varietal  characteristic,  and  partly  a  result  of  the  non-irrigated  con- 
dition under  which  they  are  grown  in  Alameda  County.  Trophy  is 
earlier  than  most  strains  of  San  Jose  Canner,  and  in  cool  regions  is 
more  productive. 

Italian  Varieties. — Much  interest  has  been  aroused  in  the  United 
States  in  recent  years  concerning  certain  Italian  varieties,  due  to 
extensive  imports  of  canned  tomatoes  and  tomato  products  from  that 
country.  The  Italian  varieties  most  suitable  for  a  solid  pack,  of  small 
whole  fruit  used  for  salads,  are  Princess  Borghese  and  King  Humbert. 
The  fruit  of  these  varieties  is  about  twice  as  large  as  the  common 
Red  Pear,  but  smaller  than  Earliana.  They  are  of  superior  color  and 
solidity.  They  are  elongated  in  shape,  with  only  two  cells,  and  are  borne 
in  large  clusters.  Some  Italian  varieties,  especially  the  Humbert,  have 
a  higher  content  of  solids  than  American  varieties,  which  is  a  valuable 
feature  from  the  manufacturer's  viewpoint.  Princess  Borghese,  how- 
ever, has  a  rather  low  solid  content.  An  outstanding  characteristic 
of  these  tomatoes  is  their  ability  to  remain  on  the  plant,  sound  and 
firm,  for  weeks  after  they  attain  full  color.  Their  moisture  content 
does  not  change  appreciably  during  this  period.  The  main  objection 
to  the  growing  of  such  varieties  is  the  high  cost  of  picking  the  small 
fruits.  This  is  partly  balanced  by  the  fact  that  only  a  few  pickings  are 
necessary,  as  the  fruit  can  be  left  on  the  plant  until  a  large  part  of 
it  is  ripe.  Other  Italian  varieties  tested  at  Davis  are  inferior  in  size, 
uniformity,  and  yield,  to  the  ordinary  California  types. 


GROWING    THE    PLANTS 

For  the  sake  of  economy  of  seed,  earliness,  and  convenience  in 
growing  the  crop,  the  plants  are  usually  grown  in  beds  of  one  kind 
or  another,  from  which  the  plants  are  transplanted  to  the  field  at  the 
proper  time  in  spring,  usually  after  danger  of  frost  is  past.  The  best 
method  of  growing  the  plants  depends  on  the  locality  and  the  season 
at  which  the  crop  is  desired. 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


11 


i  i* 


Fig.  5. — This  shows  the  irregular  or  rough  blossom  ends,  with  large  stylar 
scar,  which  is  commonly  found  in  the  old  types  of  San  Jose  Canner  variety. 


(From  Hilgardia,  vol.  2,  no.  2.) 


Fig.  6. — View  of  the  fruit  from  an  improved  strain  of  San  Jose  Canner 
variety,  which  has  been  selected  over  a  period  of  years  for  smoothness  and 
large  size.     (From  Hilgardia,  vol.  2,  no.  2.) 


12  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

The  Hotbed-C  old  frame  Method. — The  hotbed-coldframe  method  is 
generally  best  for  early  market  crops,  and  is  also  used  even  for  the  late 
shipping  and  canning  crop  in  central  and  northern  California.  This 
method  is  described  in  detail  herein,  because  its  more  extensive  use 
seems  desirable.  The  hotbed  frame  should  be  located  in  a  warm, 
sunny,  well  drained  spot.  The  best  covering  for  the  hotbed  is  glazed 
sash,  but  unbleached  muslin  (grade  DD)  is  also  satisfactory,  especially 
if  treated  with  a  waterproofing  compound.  About  one  foot  of  fresh, 
hot,  horse  manure  is  placed  in  the  bed,  tramped  down,  and  a  layer  of 
soil  four  inches  deep  placed  over  this.  It  is  best  to  use  a  sandy  soil 
or  a  mixture  of  one-half  sand  and  one-half  garden  soil  in  the  hotbed. 
This  gives  stronger  plants,  with  better  root  systems,  than  does  a  very 
fertile  or  heavy  soil.  The  seed  usually  is  planted  early  in  January, 
three  months  or  more  before  time  of  field  setting.  It  is  sown  broad- 
cast, or  drilled  into  rows  about  four  inches  apart  and  covered  about 
one-half  inch  deep.  If  good  seed  is  sown  is  sown  at  the  rate  of  12  or 
15  per  inch  of  row,  one  hotbed  6  by  24  feet  in  size  should  produce 
about  50,000  seedlings.  The  hotbed  should  be  kept  warm  and  moist 
until  the  plants  are  up,  after  which  time  it  should  be  well  ventilated 
during  warm  days,  and  watered  sparingly. 

As  soon  as  the  seedlings  show  their  first  rough  leaves,  they  are 
ready  to  transplant  to  another  bed,  usually  a  coldframe  (fig.  7). 
This  is  a  task  that  is  worth  doing  well  and  carefully.  The  coldf rames 
are  prepared  much  like  the  hotbeds  except  that  no  manure  is  placed 
under  them.  A  suitable  covering  for  the  frames  may  be  made  of 
unbleached  muslin  sewed  together  in  sheets,  or  tacked  on  to  frames 
of  convenient  size  for  handling.  About  four  inches  of  fine  soil  should 
be  placed  in  the  coldframe,  preferably  a  mixture  of  one  part  garden 
soil,  one  part  sand,  and  one  part  rotted  manure,  all  well  mixed  and 
passed  through  a  screen  of  one-half  inch  mesh.  The  seedling  plants 
from  the  hotbed  are  set  in  the  bed  about  two  by  four  inches  apart 
usually. 

Watering  should  follow  transplanting  and  the  frames  are  kept 
covered  a  few  days,  until  the  plants  have  taken  root.  This  is  especi- 
ally necessary  if  the  sun  is  warm  or  the  weather  windy.  After  the 
plants  have  begun  to  grow,  the  frames  should  be  ventilated  freely 
during  the  daytime,  and  watered  only  enough  to  keep  the  plants 
growing  at  a  moderate  rate.  When  the  plants  are  about  ten  inches 
high,  the  beds  should  be  gone  over  and  the  terminal  bud  pinched  out 
of  each  plant.  This  prevents  the  plants  from  growing  any  taller  and 
encourages   the   development   of   thick,   stout   stems   and   good   root 


Circ.  263] 


TOMATO    PRODUCTION   IN    CALIFORNIA 


13 


systems.  At  the  same  time,  shoots  begin  to  develop  in  the  axils  of  the 
leaves.  In  this  manner,  the  framework  for  a  large  bushy  plant  is 
started  before  the  plants  are  set  in  the  field.  This  treatment  of 
"topping"  the  plants  two  or  three  weeks  before  transplanting  to  the 
field  has  been  found,  in  experiments,  to  result  in  considerable  increases 
in  yield  of  early  fruit. 


Fig.  7. — The  type  of  coldframes  used  for  plant  growing  in  central  and 
northern  California.  They  are  8  to  12  feet  wide;  the  sides  and  ends  consist 
of  1  x  12  inch  boards;  and  the  frames  are  covered  with  sheets  of  unbleached 
muslin.  The  seedling  plants  from  the  hotbeds  should  be  transplanted  into  these 
coldframes,  about  3  inches  by  4  inches  apart.     (From  Agr.  Exp.  Sta.  Circ.  280.) 

A  variation  in  the  hotbed  method  as  described  above  is  to  trans- 
plant the  seedlings  into  small  clay  pots  or  into  "dirt  bands"  from 
which  the  plants  can  be  transplanted  without  disturbing  the  roots. 


14  UNIVERSITY   OP    CALIFORNIA — EXPERIMENT    STATION 

Although  more  expensive,  this  method  may  be  profitable  to  the  market 
gardener  who  caters  to  a  demand  for  extra-early  fruit  on  a  local 
market.  Another  method  is  to  transplant  the  seedlings  to  "flats," 
boxes  about  18  by  24  inches  in  size,  and  3  inches  deep.  This  is  a 
satisfactory  way  to  grow  plants  for  sale,  as  is  done  by  many  gardeners 
and  seedsmen. 

For  a  week  or  ten  days  before  transplanting  the  plants  to  the  field, 
the  beds  should  be  left  open  day  and  night,  unless  frost  threatens, 
and  only  enough  water  applied  to  keep  the  plants  from  prolonged 
wilting.  This  treatment  toughens  or  "hardens"  the  plants  so  that 
they  will  stand  transplanting  without  severe  wilting,  which  so  often 
kills  tender  plants  when  set  in  the  open  field.  Well-hardened  plants 
are  slightly  more  resistant  to  frost  than  soft  succulent  ones,  and  they 
also  take  root  and  begin  to  grow  more  rapidly. 

The  Coldframe  Method. — Tomato  plants  may  be  started  in  cold- 
frames  where  they  have  to  be  sown  during  cool  weather  but  not  so 
early  as  to  require  the  hotbed  method.  Frames  are  prepared  running 
east  and  west  in  a  sheltered  sunny  spot.  A  four-inch  layer  of  sandy, 
moderately  fertile  soil  should  be  placed  in  the  frames.  The  seed  is 
sown  by  hand  or  with  a  seed  drill,  being  planted  thinly  in  rows  four 
to  six  inches  apart.  After  germination,  the  beds  should  be  weeded 
and  the  plants  thinned  to  about  three  plants  to  the  inch.  This  method 
can  be  used  to  produce  large  numbers  of  plants  cheaply,  but  good 
large  stocky  plants  with  well-developed  roots  are  seldom  grown  in  this 
way,  the  seed  being  usually  planted  too  thick  and  the  growers  failing 
to  do  the  necessary  thinning.  The  plants  are  pulled  and  transplanted 
directly  to  the  field  from  the  coldframe. 

The  Open  Bed  Method. — This  is  probably  the  cheapest  way  to 
grow  plants  but  it  is  not  adapted  to  sections  having  short  growing 
seasons,  nor  to  early  crop  production.  It  is  used  for  growing  plants 
for  the  late  shipping  crop  in  southern  California,  and  may  also  be 
suitable  for  late  market  crops  elsewhere,  when  relatively  quick-matur- 
ing varieties  like  Marglobe  and  Norton,  are  used.  For  the  open  bed 
method,  beds  are  prepared  in  a  well-drained  sheltered  spot,  preferably 
where  the  soil  is  sandy.  Narrow  beds,  thirty  to  thirty-six  inches  from 
center  to  center,  are  thrown  up  with  a  lister,  the  ridges  are  harrowed 
down  and  levelled  with  a  planker,  and  two  rows  are  sown  on  each  bed. 
The  furrow  between  the  beds  is  used  for  irrigation.  The  seed  is 
drilled  in  with  a  seeder  as  soon  as  the  soil  warms  up  and  danger  of 
frost  is  over.  It  is  very  important  to  see  that  the  seed  is  not  planted 
too  thickly  even  in  these  open  beds,  and  thinning  should  be  practiced 
where  the  plants  stand  too  thick. 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


15 


Care  of  Plant  Beds. — Plant  beds,  whether  covered  or  open  type, 
must  be  weeded  and  cultivated  to  prevent  crust  formation  around  the 
plants.  Thinning  the  plants  is  often  necessary,  for  if  crowded  they 
develop  weak  spindling  stems,  resulting  in  plants  of  very  poor  quality. 
Particular  care  should  be  given  to  the  watering  of  plant  beds,  for 
overwatering  results  in  weak,  sappy,  leggy  plants  that  are  hard  to 
transplant  to  the  field  and  which  recover  slowly  if  they  survive  trans- 
planting. Excessive  moisture,  especially  if  given  late  in  the  day, 
encourages  "damping  off,"  a  disease  which  sometimes  destroys  many 


Fig.  8. — This  shows  the  more  rapid  growth  of  plants  from  seeds  sown 
directly  in  the  field  on  May  1  (at  the  left),  compared  to  plants  of  the  same 
age  but  transplanted  from  a  seed  bed  (at  the  right).  The  difference  in  size 
of  plants  gradually  disappears  later  in  the  season.  Photographed  June  18,  at 
Riverside.     (Courtesy  of  M.  Shapovalov.) 

plants  overnight.  Waterings  should  be  given  usually  several  days 
apart,  and  not  until  the  plants  have  begun  to  wilt.  No  harm  is  done 
if  the  plants  are  checked  temporarily  by  lack  of  water.  However, 
holding  plants  for  a  long  period  after  they  have  reached  transplanting 
size  is  undesirable.  For  this  reason,  it  is  advisable  not  to  plant  earlier 
than  necessary  to  get  plants  of  the  correct  size  for  transplanting  at 
the  desired  time.  Ten  to  twelve  weeks  should  be  allowed  for  plant 
growing. 

The  day  before  transplanting  to  the  field,  the  beds  should  be 
soaked  well  so  that  the  plants  can  be  removed  easily.  In  taking  up 
the  plants,  it  is  better  to  dig  them  with  a  spade,  rather  than  to  pull 
by  hand,  which  is  the  too  general  practice. 


16  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Seeding  Directly  in  the  Field. — In  sections  having  a  long  season, 
tomatoes  may  be  planted  directly  in  the  field.  This  method  is  wasteful 
of  seed,  involves  considerable  labor  in  thinning,  and  cannot  be 
practiced  when  tomatoes  follow  a  winter  crop  of  spinach  or  other 
vegetables.  On  the  other  hand,  direct  field  planting  saves  the  cost 
of  hotbeds  and  of  transplanting,  and  the  growth  of  the  plants  is  not 
delayed  by  the  transplanting  process  (fig.  8).  It  is  a  cheap  way  to 
produce  an  excess  number  of  plants,  where  there  is  danger  of  loss 
from  the  yellows.     Non-transplanted  tomatoes  also  develop  a  deep 


Fig.  9. — The  root  systems  of  tomato  plants.  The  one  at  the  left  was  trans- 
planted from  the  hotbed.  It  has  no  taproot,  but  does  have  a  number  of  shallow 
laterals.  At  the  right  is  shown  a  plant  from  direct  field  planting.  It  has  a 
long  taproot,  and  the  laterals  are  deep. 

tap  root  (fig.  9),  whch  gives  them  an  advantage  under  dry-farming 
conditions.  Only  varieties  that  mature  in  a  medium  or  short  season 
should  be  grown  this  way,  unless  the  season  is  very  long.  The  seed 
is  planted  in  hills  early  in  March  before  danger  of  frost  is  over. 
Later,  the  plants  are  thinned  to  two  in  a  hill.  At  Davis,  about  the 
same  yields  of  ripe  fruit  were  obtained  from  field-planted  and  from 
hotbed-grown  plants,  in  two  years'  tests. 

In  the  Imperial  Valley,  almost  the  entire  acreage  is  ordinarily 
grown  from  November  plantings  made  directly  in  the  field.  They  are 
protected  with  brush  and  paper  shelters,  as  shown  in  figure  10,  until 
danger  of  frost  is  past. 


Circ.  263] 


TOMATO    PRODUCTION   IN    CALIFORNIA 


17 


FIELD   CULTURE 

Except  where  following  spinach  or  other  winter  crops,  tomato  land 
should  be  fall-plowed  as  deeply  as  possible.  In  spring,  before  the 
surface  gets  hard  and  dry,  the  land  should  be  disked  and  floated  to 
kill  weeds  and  to  get  the  surface  into  fine  condition,  and  level.  The 
method  of  preparing  for  the  plants  and  method  of  transplanting 
depends  upon  the  locality  and  the  soil  conditions.  In  some  sections, 
when  planting  for  the  early  crop,  it  is  easy  to  set  the  plants  without 
watering  if  the  soil  is  handled  properly.  Under  such  conditions,  the 
field  is  prepared  level  and  marked  off  in  both  directions  and  the  plants 


Fig.  10. — Method  of  protecting  tomatoes  sown  directly  in  the  field,  in 
Imperial  Valley.  The  seed  is  planted  in  hills  on  the  south  side  of  beds  running 
east  and  west.     Thinning  is  deferred  until  danger  of  frost  is  over,  in  February. 


set  at  the  intersections,  if  they  are  set  by  hand.  In  setting  large 
acreages,  however,  much  time  and  labor  can  be  saved  by  the  use  of  a 
horse-drawn  transplanter.  These  machines,  of  which  there  are  several 
types  on  the  market,  set  the  plants  as  well  as  they  are  usually  set  by 
hand,  and  can  be  used  also  to  water  the  plants,  if  necessary. 

In  dry  sections,  and  in  most  sections  during  dry  seasons,  it  is 
necessary  to  water  the  plants  as  they  are  transplanted.  This  is  almost 
always  the  case  in  setting  the  late  crop.  If  irrigation  is  practicable, 
the  simplest  plan  is  to  plow  out  a  furrow  for  each  row.  The  plants 
are  set  the  proper  distance  apart  on  the  edge  of  the  furrow  and  a 
small  stream  of  water  is  turned  into  each  row  as  it  is  set.  Cultivation 
must  follow  within  a  day  or  two  to  prevent  a  hard  crust  forming 
around  the  roots.  At  this  time  the  soil  should  be  worked  toward  the 
plants,  thus  beginning  the  bed  which  should  be  gradually  formed  for 
each  row. 


18  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 

Another  way  to  set  plants  under  dry  conditions  is  to  haul  a  number 
of  barrels  of  water  into  the  field  and  place  them  at  convenient  inter- 
vals. As  the  plants  are  set,  a  little  water  is  poured  about  the  roots. 
In  transplanting  tomatoes,  the  roots  should  be  covered  as  deeply 
as  possible,  usually  setting  the  plants  three  or  four  inches  deeper  than 
they  were  in  the  plant  bed.  New  roots  develop  along  the  stem,  giving 
the  plant  a  more  extensive  root  system  than  can  be  obtained  when  the 
plants  are  set  shallow.  Deep  setting  is  of  course  more  laborious  than 
the  customary  shallow  setting,  but  it  enables  the  plants  to  make  use 
of  the  moisture  in  the  lower  soil.  Deep  plowing,  or  sub-soiling  also 
aids  in  securing  deep  penetration  of  the  roots.  Plants  with  deep  roots 
are  most  assured  of  an  even  moisture  supply,  do  not  require  so 
frequent  irrigations,  and  do  not  suffer  from  the  sharp  fluctuations 
of  alternately  having  too  much  and  too  little  water.  Some  of  the 
troubles  affecting  tomatoes  result  from  too  shallow  root  systems. 

Irrigation. — In  some  parts  of  the  state,  satisfactory  tomato  crops 
can  be  grown  with  little  or  no  irrigation,  if  the  plants  are  given 
a  chance  to  develop  deep  root  systems.  This  is  true  of  the  San  Fran- 
cisco Bay  and  other  cool  regions  with  over  15  inches  of  winter  rain- 
fall. However,  in  most  sections  some  irrigation  gives  larger  yields. 
The  number  and  frequency  of  irrigations  is  determined  mostly  by 
local  conditions.  Enough  water  should  be  applied  to  keep  the  plants 
growing  steadily.  Too  frequent  irrigation  may  favor  excessve  vine 
growth  and  sometimes  causes  the  blossoms  to  drop  without  setting 
fruit.  The  best  method  is  to  open  a  furrow  alongside  each  row 
(fig.  11),  as  close  to  the  plants  as  possible,  so  that  the  moisture  can 
seep  down  to  the  roots.  Cultivation  should  follow  promptly,  throw- 
ing the  soil  toward  the  plants.  For  each  successive  irrigation,  the 
furrow  is  made  further  from  the  plants  and  by  mid-season  a  broad 
low  bed  has  been  formed,  which  is  covered  by  the  sprawling  plants 
(figs.  12  and  13).  Between  the  beds  is  the  dead-furrow  which  may 
be  used  for  later  irrigations,  allowing  the  water  to  penetrate  to  the 
roots  without  wetting  the  surface  on  which  vines  and  fruit  are  resting. 

The  first  irrigation  after  the  one  given  at  transplanting  time, 
should  usually  be  deferred  until  after  the  plants  have  begun  to 
set  fruit.  The  number  and  frequency  of  the  irrigations  thereafter 
depends  upon  soil  and  climatic  conditions.  On  heavy  soils  in  the 
Sacramento  and  Santa  Clara  Valley,  three  irrigations,  of  four  or 
five  acre-inches  each,  may  suffice  for  the  entire  season.  On  lighter  soils 
in  the  San  Joaquin  and  Imperial  Valleys,  where  evaporation  is  very 
high,  an  irrigation  may  be  necessary  every  two  weeks. 


Cmc.  263] 


TOMATO    PRODUCTION   IN    CALIFORNIA 


19 


Fig.  11. — Tomatoes  furrowed  for  the  first  irrigation  after  transplanting. 
Fruit  setting  has  already  begun  on  these  plants. 


Fig.  12. — Irrigation  of  tomatoes  from  slip-joint  pipe.  By  the  use  of  a  V- 
crowder,  a  basin  two  feet  wide  has  been  made  between  the  rows.  This  is 
advisable  where  the  land  slopes  very  steeply.  As  the  lateral  movement  of 
moisture  is  negligible,  a  furrow  close  to  the  plants,  however,  would  be  more 
effective.  After  a  run  of  six  hours,  the  moisture  had  not  penetrated  more  than 
six  inches  to  each  side  of  this  basin. 


20 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


There  are  two  periods  at  which  water  generally  should  not  be 
applied — during  the  period  when  the  first  flowers  are  open,  and  during 
the  later  part  of  the  fruit-ripening  period.  Irrigation  at  the  earlier 
period  will  decrease  the  set  of  fruit,  and  at  the  later  period  may 
retard  the  maturing  of  the  crop.  However,  in  some  sections  where 
the  crop  is  grown  for  late  fall  shipment,  the  practice  is  to  irrigate 
just  as  the  first  cluster  begins  to  bloom.  This  prevents  the  setting  of 
early  fruit  and  may  encourage  the  development  of  a  larger  plant  that 
will  produce  more  late  fruit. 


W<^a^ri^v&i> 


<§mmm 


Fig.  13.     Tomatoes  furrowed  for  late  irrigation.     There  are  plenty  of 
tomato  roots  in  the  row  middles  at  this  time. 


Planting  Distances. — The  planting  distance  is  determined  by  the 
variety,  the  soil,  and  the  season  at  which  the  crop  is  grown.  Early 
tomatoes  grown  under  intensive  culture,  where  the  plants  are  staked 
and  trained  to  a  single  stem,  as  in  the  Merced  district,  are  set  15  inches 
by  3  feet  apart,  thus  requiring  about  12,000  plants  per  acre.  Early 
varieties  where  not  staked  and  pruned,  are  usually  set  about  3  by  4 
feet,  requiring  3,600  plants  per  acre.  The  late  shipping  and  canning 
crop  of  such  varieties  as  Stone,  which  generally  make  vigorous  vine 
growth,  are  set  6  by  6  feet,  and  the  San  Jose  Canner  requires  6  by  8, 
to  8  by  8  feet.  The  late  varieties  then  require  from  700  to  1,200  plants 
per  acre.  Further  modification  may  be  necessary  on  account  of  mois- 
ture and  fertility  conditions.  Under  dry-farming  conditions,  wider 
spacing  is  desirable  than  under  irrigation. 

Wider  spacings  are  more  economical  of  plants  and  labor  than  the 
closer  plantings.  Yet  there  are  no  reliable  data  available  to  indicate 
when  wide  or  close  plantings  will  pay  best.  Certainly  the  rows  must 
be  wide  enough  to  allow  cultivation  and  irrigation  and  to  permit  easy 
passage  for  the  pickers  without  tramping  upon  the  plants.  Experi- 
ments in  which  two  plants  are  set  in  a  place  show  slightly  less  yield 
from  the  two  than  from  a  single  plant. 


Circ.  263] 


TOMATO   PRODUCTION   IN    CALIFORNIA 


21 


STAKING   AND   PRUNING 

The  tomato  plant  naturally  forms  an  erect  central  stem,  with  side 
branches  developing  from  the  axil  of  each  leaf.  Under  the  special 
form  of  culture  known  as  staking  and  pruning,  the  side  shoots  are 
pinched  out  as  they  appear.  The  growth  is  thus  limited  to  the  main 
or  central  stem,  which  is  kept  erect  by  tying  it  at  intervals  to  a  stake 
placed  alongside  each  plant  as  shown  in  figure  14.  On  such  plants, 
the  crop  is  limited  to  the  fruit  born  in  the  clusters  which  form  at 
every  third  or  sixth  node  on  the  central  stem.    Naturally,  this  reduces 


Fig.  14. — Staked  tomatoes,  at  about  the  time  the  first  cluster  is  ripening. 
The  lower  leaves  have  been  cut  off,  to  expose  the  fruit  to  the  sun.  The  plants 
may  also  be  topped  above  the  sixth  cluster  at  this  stage. 


greatly  the  number  of  fruits  that  a  plant  can  bear,  but  this  is  partly 
offset  by  the  closer  spacing  of  the  plants  which  this  method  of  culture 
permits.  Plants  to  be  staked  and  pruned  may  be  set  15  to  18  inches 
apart  in  rows  3  feet  wide.  This  gives  three  or  more  times  as  many 
plants  per  acre  as  an  early  variety  grown  without  staking  and  prun- 
ing. It  is  claimed  that  staking  and  pruning  results  in  increased 
earliness,  greater  production  of  early  fruit,  and  larger  fruit,  than  do 
plants  allowed  to  grow  naturally.  On  the  other  hand,  staking  and 
pruning  results  in  higher  costs  of  production  per  acre  for  labor, 
plants,  and  materials.     This  treatment  may  result  in  increased  loss 


22  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

from  mosaic  and  from  blossom-end  rot  diseases.  Furthermore,  under 
California  conditions  it  gives  a  lower  total  yield  for  the  season,  and 
the  increase  in  early  production  may  be  more  apparent  than  real, 
when  considered  on  the  basis  of  yield  to  the  plant,  rather  than  on 
that  of  yield  to  the  acre.  The  staking  and  pruning  method  of  culture 
should  be  limited  to  home  gardens  and  to  early-market  crops  when 
the  area  available  is  very  limited. 


FERTILIZERS   AND    MANURES 

The  tomato  crop  in  California  is  generally  not  manured  or  treated 
with  commercial  fertilizers.  There  is  very  little  experimental  work 
to  guide  fertilizer  practices  with  this  crop  on  our  soils.  It  is  evident, 
however,  that  upon  most  soils,  and  in  most  localities  in  the  state, 
tomato  plants  make  satisfactory  vegetative  growth  and  produce  large 
crops  of  fruit,  without  artificial  fertilization,  when  moisture  and  other 
factors  are  properly  cared  for.  An  exception  to  this  may  be  found 
on  some  of  the  light  sandy  or  gravelly  soils  in  the  southern  part 
of  the  state,  where  it  has  been  found  that  tomatoes  respond  with 
increased  growth  and  larger  yields,  when  nitrogenous  fertilizers  are 
applied.  In  cases  where  the  plant  growth  is  unsatisfactory,  the  cause 
should  first  be  sought  by  determining  if  injury  is  being  caused  by 
hardpan,  poor  drainage  or  irrigation,  alkali,  or  disease.  The  history 
of  the  soil,  whether  or  not  other  annual  crop  plants  grown  on  it 
respond  to  fertilizer  applications,  may  also  serve  to  indicate  the 
requirements  for  tomatoes.  Two  common  misconceptions  about  the 
fertilization  of  tomatoes,  namely,  that  the  injurious  effects  of  too  much 
nitrogen  can  be  overcome  by  adding  more  of  some  other  element,  and 
that  potassium  fertilizers  have  some  particular  effects  upon  solidity 
and  shipping  quality,  have  been  disproved. 

Where  a  commercial  fertilizer  is  to  be  used,  the  best  method  of 
applying  it,  usually  is  to  drill  it  into  the  row  where  the  plants  are  to 
go,  and  mix  it  with  the  soil  before  the  plants  are  set.  A  fertilizer  is 
generally  most  effective  if  it  is  placed  where  the  roots  will  obtain  it 
in  the  early  part  of  the  growing  season.  When  the  soil  is  deficient 
in  nitrogen,  the  cheapest  and  most  effective  form  in  which  it  can  be 
supplied,  under  California  conditions,  is  in  ammonium  sulfate.  Three 
hundred  pounds  per  acre  of  this  material  is  usually  a  maximum 
application. 


Circ.  263] 


TOMATO   PRODUCTION    IN    CALIFORNIA 


23 


HARVESTING 

The  exact  stage  of  maturity  at  which  the  fruit  is  picked  depends 
upon  the  purpose  for  which  it  is  to  be  used. 

For  sale  on  local  markets,  for  canning,  and  for  pulp  manufacture, 
the  fruit  should  be  fully  colored  but  firm  when  picked.  Nothing  is 
gained  by  leaving  the  fruit  on  the  plant  after  it  is  fully  colored. 

For  shipment  to  nearby  points  the  fruit  is  harvested  in  the  ' '  pink ' ' 
stage,  when  about  half  of  the  surface  shows  distinct  color. 


Fig.  15. — Tomatoes  wrapped  and  packed  in  "tin-tops."  Baskets  hold  about 
five  pounds  each  and  are  shipped  in  four-basket  flats.  This  package  is  suitable 
for  early  market  tomatoes,  shipped  in  the  pink  or  ripe  stage,  to  nearby  markets. 
(From  Agr.  Exp.  Sta.  Bui.  239.) 


For  shipment  to  distant  markets,  the  fruit  is  picked  usually  in 
the  "  green-mature "  stage — when  fully  grown  but  not  yet  showing 
pink  or  red  color.  Such  fruit  should,  however,  appear  yellowish  at 
the  blossom  end.  Mature  green  fruit  if  cut  open  are  found  to  have 
the  cells  well  filled  with  the  gelatinous  pulp  in  which  the  seed  is 
embedded. 

To  pick  tomatoes  for  shipment,  the  fields  are  generally  gone  over 
once  a  week,  and  fruit  in  all  of  the  above  stages  of  ripeness  gathered 
at  once.  The  ripe  fruit,  however,  is  placed  in  separate  containers  by 
the  picker,  and  is  disposed  of  on  the  local  market  or  to  the  canner. 
The  pink,  turning,  and  green  fruit  is  hauled  to  the  packing  shed, 
where  it  is  sorted,  graded,  wrapped,  and  packed  for  shipment.  This 
part  of  handling  the  crop  can  generally  be  taken  care  of  through  a 


24  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

local  cooperative  packing  and  shipping  association,  or  by  a  reputable 
distributing  organization,  better  than  by  the  individual  grower. 

Great  care  should  always  be  taken  in  handling  tomatoes  for  any 
or  all  purposes,  to  avoid  bruising  or  breaking  the  skin.  The  pickers 
should  remove  the  stem  from  the  fruit  as  it  is  picked,  to  prevent 
puncturing  the  skins  of  other  fruit. 

Packing. — Persons  interested  in  the  packing  and  shipping  of 
tomatoes  shoud  secure  Farmers'  Bulletin  1291  from  the  United  States 
Department  of  Agriculture,  Washington,  D.  C.  The  two  types  of 
containers  most  used  in  California  are  the  four-basket  flats,  shown  in 
figure  15,  and  the  Los  Angeles  or  Mexican  lug,  figure  16.  The  latter 
is  used  mainly  for  eastern  shipments.  Cannery  tomatoes  are  handled 
in  50-pound  lug-boxes,  which  are  supplied  to  the  growers  by  the 
canners  at  a  nominal  rental. 

Artificial  Ripening. — Fruit  picked  in  the  green-mature  stage  ripen 
and  color  up  within  one  to  three  weeks,  depending  upon  the  tempera- 
ture and  the  degree  of  maturity  when  picked.  The  quality  of  such 
fruit  is  good  when  ripened  in  air,  but  when  wrapped  in  tissue  paper, 
as  is  the  usual  commercial  practice,  the  flavor  and  texture  of  the 
artificially  ripened  fruit  may  be  unsatisfactory.  Upon  arrival  at 
market,  the  fruit  is  unwrapped;  that  showing  sufficient  color  is  sold 
at  once,  while  that  which  is  still  green  or  only  partly  colored  is  placed 
in  special  ripening  rooms.  Another  defect  in  the  practice  of  picking 
and  shipping  green-mature  tomatoes  is  that  careless  pickers  gather 
many  that  are  not  mature.  The  latter  are  worse  than  a  dead  loss  to 
the  grower,  for  they  never  attain  good  edible  quality  when  artificially 
ripened.  Tomatoes  picked  in  the  "turning"  stage,  when  they  show 
a  little  pink  color  at  the  blossom  end,  are  more  uniformly  of  high 
quality  when  artificially  ripened,  than  those  picked  green. 

The  most  favorable  temperature  for  rapd  ripening  of  tomatoes  is 
between  70°  and  80°  F.  Below  60°,  the  ripening  process  is  very 
slow.  The  maximum  storage  life  of  the  tomato  is  obtained  with  a 
temperature  between  50°  and  55°  F.  If  stored  at  temperatures  below 
50°  F  for  more  than  a  few  days,  the  fruit  does  not  color,  but  decays 
upon  removal  to  a  higher  temperature.  Prolonged  cold  storage  of 
cither  green  or  ripe  tomatoes  is  therefore  impracticable. 

The  ripening  of  tomatoes  in  storage  can  be  greaty  accelerated  by 
adding  small  amounts  of  ethylene  gas  to  the  air  of  the  storage  room. 
A  concentration  of  one  part  ethylene  to  4,200  parts  of  air  has  been 
found  effective,  reducing  by  about  one  half  the  time  required  to  change 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


25 


tomatoes  from  the  green  to  full  red  color.  The  gas  is  obtained  in 
compressed  form  in  steel  cylinders,  from  which  the  proper  amount 
of  gas  is  discharged  into  the  ripening  room  each  day.  The  room  has 
to  be  approximately  airtight  to  prevent  the  too  rapid  loss  of  the  gas. 


Fig.  16. — A  tomato  packing  room,  showing  convenient  arrangement  of  grad- 
ing bins,  movable  packing  tables,  box  chutes,  and  conveyors  for  the  packed 
boxes.  At  the  right  are  packed  30-pound  Los  Angeles  lug-boxes.  This  package 
is  used  for  shipment  of  green  fruit  to  distant  markets,  where  the  fruit  is 
unwrapped,  sorted,  ripened,  and  repacked  in  smaller  containers  for  retailing. 
(Courtesy  of  R.  G.  Risser.) 


26 


UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 


Oxygen  is  also  essential  for  normal  ripening,  so  a  fresh  supply  of  air 
should  be  admitted  each  day.  Temperatures  favorable  to  the  ripening 
process  have  to  be  maintained  in  the  ripening  room,  even  when 
ethylene  is  used.  Ethylene  is  explosive  in  mixtures  of  1  to  3  in  air, 
but  is  not  dangerous  or  explosive  in  the  low  concentrations  used  in 
ripening  tomatoes. 


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Fig.  17. — Carlot  shipments  of  tomatoes  from  the  chief  shipping  sections,  by 
weeks,  for  the  season  of  1927.  From  December  to  May,  the  markets  are 
supplied  almost  entirely  by  Florida  and  Mexico. 


SHIPPING   SEASONS 

To  make  clearer  the  opportunities  for  tomato  production  for  ship- 
ment to  outside  markets,  and  to  show  the  relation  of  tomato  shipments 
from  California  to  those  from  other  sections  and  from  the  United 
States  as  a  whole,  the  carlot  shipments  from  the  leading  tomato 
districts  are  shown  in  figure  17.  While  minor  changes  in  volume  and 
season  occur  from  year  to  year,  the  general  shipping  cycle  remains 
about  the  same. 

Tomatoes  are  shipped  throughout  the  year,  but  from  December  to 
May  the  markets  are  supplied  almost  entirely  by  Florida  and  Mexico. 
Shipments  from  other  sections  gradually  increase  during  the  spring 


CIRC.  263]  TOMATO   PRODUCTION   IN    CALIFORNIA  27 

until  a  peak  is  reached  in  June.  Thereafter,  they  decrease  and  the 
total  number  of  cars  shipped  during  July  and  August  is  relatively 
low.  This  is  the  period  of  local  production  in  the  North  and  East, 
so  that  carload  shipments  from  outside  districts  are  not  needed.  Late 
in  August  the  market  on  tomatoes  improves,  due  to  exhaustion  of 
home-grown  supplies  in  the  East  and  South.  This  leads  to  a  second 
peak  of  shipments  during  the  fall,  which  declines  rapidly  as  frost  cuts 
down  one  shipping  section  after  another.  By  the  middle  of  December 
the  only  shipments  of  any  importance  are  those  from  Mexico.  It  is 
noted  in  figure  19  that  shipments  of  early  tomatoes  in  California  are 
not  very  important,  due  to  heavy  production  in  other  sections  nearer 
the  big  markets  of  the  country.  However,  after  the  first  week  of 
October,  California  is  the  only  important  shipper  of  tomatoes.  For 
a  period  of  two  months  in  the  fall,  California  tomatoes  have  command 
of  the  markets  of  the  entire  country.  Production  for  shipment  in 
this  period  seems  especially  promising. 


SEED   GROWING 

Comparatively  few  tomato  growers  now  select  and  save  seed  for 
their  own  use.  Yet  it  is  often  well  to  do  this,  and  do  it  carefully,  in 
order  to  develop  an  improved,  acclimated  strain. 

Although  tomatoes  are  very  largely  self -pollinated,  some  crossing 
does  take  place  when  different  varieties  are  grown  near  each  other. 
The  amount  of  crossing  varies  from  0.2  to  5  per  cent,  depending  upon 
the  variety  and  on  the  number  of  insects  (mainly  bumble  bees)  which 
visit  the  flowers.  Accordingly,  the  seed  plot  should  be  isolated  from 
other  varieties. 

Many  varieties  contain  plants  varying  a  great  deal  in  vigor  and 
yield,  as  well  as  in  quality  and  type  of  fruit.  Some  seed  stocks  are 
actually  mixed,  containing  plants  of  poor  type  or  low  yield  or  of 
different  varieties.  The  procedure  recommended  is  to  mark  certain 
plants  that  show  vigor,  health  and  earliness,  about  the  time  the  fruit 
begins  to  ripen.  The  pickers  are  then  instructed  to  take  no  fruit  from 
the  marked  plants.  A  second  inspection,  two  or  three  weeks  later, 
will  enable  one  to  judge  of  the  productivity,  quality  and  type  of  fruit. 
The  fruit  should  have  desirable  internal  characteristics  (fig.  18,  A). 
and  should  not  show  the  ' '  puffy ' '  condition  (fig.  19 ) .  The  plants  which 
seem  desirable  from  this  standpoint  are  retained,  while  the  other  plants 
marked  at  the  first  selection  are  discarded.  It  is  best  to  save  separ- 
ately, and  to  plant  one  row  in  the  field  the  next  year  with  seed  from 


28  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

each  of  the  selected  plants.  The  rest  of  the  seed  from  the  selected 
plants  can  be  mixed  and  used  for  the  main  planting.  From  the  best 
row  the  next  year,  seed  is  saved  in  sufficient  quantity  for  the  entire 
planting  the  third  year.  Practically  all  of  the  benefit  derived  from 
selection  is  apparent  in  the  tomato  the  first  year  after  selection  is 
made.  Selection  simply  isolates  the  best  qualities  present  in  the 
original  variety,  and  the  improvement  over  the  average  is  usually 
sufficient  to  make  the  practice  quite  profitable.  However,  selection 
should  be  continued  from  year  to  year  to  eliminate  any  degenerate 
plants  and  to  preserve  and  improve,  if  possible,  the  qualities  of  the 
original  selection.  Indiscriminate  selection  of  good  fruits  without 
reference  to  vigor,  health,  yield,  and  type  of  the  plant  from  which  the 
fruit  came  will  not  result  in  much  improvement,  for  even  poor  plants 
may  produce  a  few  good  fruits.  There  is  generally  no  hereditary 
differences  in  seed  from  early  or  late  fruit,  or  from  large  or  small 
fruits  on  the  same  plant. 

Generally  speaking,  the  ideals  in  selecting  tomatoes  are :  first,  a 
vine  that  is  large,  vigorous,  free  from  all  disease,  and  producing  a 
large  yield  of  fruit  at  the  season  when  they  are  particularly  wanted ; 
second,  fruits  that  are  of  the  size,  color  and  shape  desired  for  the 
variety ;  third,  fruits  which  are  smooth  in  contour,  and  free  of  defects 
such  as  corky  spots,  large  scabs  or  "cat-faces."  When  cut  trans- 
versely, they  should  show  well-filled  cells  and  freedom  from  greenish 
spots  and  hard  white  cores. 

Fruit  from  which  seed  is  to  be  saved  should  be  allowed  to  ripen 
fully  on  the  vine.  When  large  quantities  are  to  be  saved  from  a 
number  of  plants,  the  ripe  fruit  is  gathered  at  intervals  and  dumped 
into  wooden  barrels,  where  it  is  pounded  into  a  pulp,  or  the  fruit 
may  be  pulped  by  pressing  through  a  grinder.  Water  should  not  be 
added — there  will  be  sufficient  juice  in  the  pulp  to  insure  speedy 
fermentation.  After  standing  until  the  gelatinous  mass  surrounding 
the  seed  is  well  decomposed,  water  is  added.  Vigorous  stirring  facili- 
tates separation  of  the  seed.  The  good  seed  sinks  to  the  bottom  while 
the  light  seeds,  skins,  and  pulp  rise  to  the  surface,  where  they  can 
be  removed  easily.  Several  successive  washings  clean  the  seed 
thoroughly,  after  which  they  should  be  drained,  spread  in  thin  layers 
on  wire  or  cloth  screens,  and  placed  in  the  sun  or  elsewhere  to  dry  as 
quickly  as  possible. 

In  cleaning  seed  on  a  larger  scale,  a  flume  with  catch  basins  is  used 
to  separate  seed  from  pulp,  and  the  seed  is  dried  in  rotating  cylinders 
through  which  a  current  of  hot  air  is  driven. 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


29 


Fig.  18. — Cross  sections  of  fruit  of  the  San  Jose  Canner  variety.  A,  large 
meaty  core  with  small  cells — a  good  type.  B,  cells  too  large — a  poor  type. 
C,  many  abortive  cells,  characteristic  of  rough  fruit — a  poor  type.  D,  large 
hard  white  core  in  center  of  fruit.     (From  Hilgardia,  vol.  2,  no.  2.) 


Fig.  19. — " Puffy"  fruit.  Note  the  air  spaces  between  the  seed  jelly  and 
the  outer  wall.  This  trouble  is  partly  a  hereditary  variety  characteristic,  and 
is  partly  due  to  cultural  conditions.     (From  Hilgardia,  vol.  2,  no.  2.) 


30  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 


DISEASES  OF  TOMATOES 

Damping  Off. — This  is  a  trouble  which  attacks  tomatoes  and  other 
plants  while  growing  in  seed  beds.  It  is  due  to  various  fungi  which 
are  often  present  in  soils.  These  fungi  attack  the  plants  at  the  surface 
of  the  soil,  causing  the  stem  to  shrivel  and  turn  black,  while  the  top 


Fig.  20. — Damping  off  of  tomato  seedlings.     Note  that  the  lower  part  of  the 
stem  is  shrivelled  and  blackened.     (From  Agr.  Exp.  Sta.  Bui.  239.) 

soon  falls  over  (fig.  20).  This  disease  is  most  likely  to  do  serious 
damage  when  the  same  soil  is  used  year  after  year  for  plant  beds.  It  is 
also  likely  to  spread  rapidly  when  the  surface  of  the  soil  is  kept  damp 
continually.  Preventive  measures  are :  using  fresh  soil  in  the  plant 
beds  each  year;  watering  plants  only  when  absolutely  necessary  and 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


31 


then  always  in  the  forenoon  so  that  plants  and  soil  surface  may  dry 
before  night;  ventilating  the  plant  beds  as  freely  as  possible  if  they 
are  covered;  and  avoiding  overcrowding  of  plants  by  transplanting 
to  proper  distance  or  by  thinning.  The  further  development  of  the 
disease,  when  it  appears,  can  be  prevented  by  sprinkling  the  surface 
of  the  soil  with  a  %  of  1  per  cent  solution  of  Semesan.  This  is  an 
organic  mercury  preparation  which  can  be  applied  to  growing  plants 
without  injury. 


Fig.  21. — Late  blight  infection  on  tomato  leaf. 
(From  Agr.  Exp.  Sta.  Bui.  239.) 


Late  Blight. — This  fungous  disease  often  appears  in  coastal  districts 
on  potatoes  and  tomatoes.  It  spreads  only  in  moist  cool  weather.  In 
southern  California  the  fall  and  winter  crop  is  very  seriously  injured 
by  this  disease,  especially  when  the  rains  come  earlier  than  usual. 
Due  to  its  irregular  appearance,  growers  are  seldom  prepared  to 
combat  it,  hence  serious  damage  results.  The  effects  of  the  disease 
appear,  soon  after  the  rains  commence,  in  the  form  of  numerous  black 
spots  on  leaves  and  stems  (fig.  21).    The  leaves  then  turn  yellow  and 


32 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


wither  or  fall  off.  If  the  weather  remains  moist,  the  whole  plant 
soon  blackens  and  dies.  The  fruit  is  also  affected.  Green  fruit  shows 
slightly  depressed  and  discolored  patches  resembling  a  bruise,  and 
these  places  develop  into  a  soft'decay  (fig.  22).  When  late  blight 
is  prevalent,  fruit  which  shows  no  visible  evidence  of  infection  at  the 
time  it  is  picked  may  develop  the  disease  during  shipment,  to  a  serious 
extent. 


Fig.  22. — Late  blight  injury  to  tomato  fruit,  in  advanced  stages  of 
infection.     (From  Agr.  Exp.  Sta.  Bui.  239.) 


Late  blight  can  be  prevented  by  spraying  the  plants  thoroughly 
with  Bordeaux  mixture  whenever  early  rains  occur  and  the  disease 
threatens.  The  spray  material  is  prepared  by  dissolving  separately, 
4  pounds  of  copper  sulfate  (bluestone)  and  4  pounds  of  unslaked 
lime  (or  6  pounds  of  hydrated  lime).  Each  solution  is  diluted  to 
25  gallons  and  the  two  are  then  poured  together,  making  50  gallons 
of  the  spray  material.  Special  spraying  machines  adapted  for  spray- 
ing two  or  three  rows  at  a  time  are  used.     They  should  have  three 


CIRC.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


33 


nozzles  for  each  row.  Tomatoes  should  be  sprayed  at  a  pressure  of 
at  least  100  pounds  per  square  inch,  to  insure  that  all  parts  of  the 
plant  are  reached  by  the  spray.  Several  applications  of  the  spray  are 
necessary  to  keep  the  new  growth  of  the  plants  protected  from  infec- 
tion. Orchard  power  sprayers  can  be  used  also  to  spray  the  tomato 
fields.  The  amount  of  spray  solution  required  for  each  application 
will  vary  from  100  to  300  gallons  per  acre,  depending  on  the  size  of 
the  plants  and  the  width  of  the  rows. 


•     *     J35P*    v'    * 

%*-*.#*  < 

Fig.  23. — A  plant  showing  early  stages  of  Fusarium  wilt.     The  tips  of 
certain  branches  are  wilting  and  the  lower  leaves  are  yellow. 

Fusarium  Wilt. — This  disease  is  caused  by  a  specific  fungus  living 
in  the  soil.  It  occurs  to  an  injurious  extent  in  many  parts  of  southern 
California  and  to  a  lesser  degree  elsewhere.  When  the  disease  once 
gets  into  a  field,  the  soil  remains  infected  and  it  spreads  rapidy  in 
succeeding  years.  However,  the  Fusarium  wilt  organism  of  tomato 
attacks  no  other  crop.  The  disease  usually  appears  a  few  weeks  after 
the  beginning  of  hot  weather,  the  lower  leaves  of  affected  plants  turn 
yellow  and  dry  up  (figs.  23  and  24).  The  stems,  if  split  open,  are 
found  to  be  brown  in  the  woody  portion.  The  disease  advances  rapidly 
and  kills  the  entire  plant,  or  only  some  of  the  main  branches.  There  is 
seldom  a  true  wilting  of  the  whole  plant,  in  the  ordinary  sense  of  the 
word,  connected  with  this  disease.  The  fungus  enters  the  plant 
through  the  roots  and  progresses  upward  through  the  plant,  which  is 
killed  by  a  toxin  excreted  by  the  fungus.  Plants  affected  early  in  the 
season  are  killed  outright,  while  those  affected  later  may  produce  a 


34  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

few  small  tomatoes.  The  control  is  to  grow  resistant  varieties,  of 
which  the  Norton  seems  best  at  present,  though  Marglobe,  an  early 
variety,  may  be  more  desirable  in  some  cases.  Some  strains  of  the 
San  Jose  Canner  are  also  resistant.  Rotation  of  crops,  growing  the 
tomatoes  on  non-infected  soil,  is  also  a  means  of  prevention.  Even 
when  resistant  varieties  are  grown,  the  plant  beds  must  be  on  non- 
infected  soil. 


Fig.  24. — Tomato  plant  in  advanced  stages  of  Fusarium  wilt. 
(From.  Agr.  Exp.  Sta.  Bui.  239.) 

V erticillium  Wilt. — In  many  respects,  the  disease  caused  by  Verti- 
cillium  resembles  the  Fusarium  wilt.  However,  Verticillium  occurs 
chiefly  in  the  cooler  districts,  as  the  San  Francisco  Bay  region,  while 
Fusarium  is  more  common  in  warmer  sections.  Verticillium  disease 
is  of  much  more  general  importance  than  Fusarium,  for  it  attacks 
many  other  crops  besides  tomatoes.  There  is  no  control  known  for 
Verticillium,  except  rotation  with  non-susceptible  crops,  such  as  the 
cereals.  Land  that  is  known  to  be  infected  should  be  avoided  for 
tomato  production. 

Boot-Knot. — This  trouble  is  caused  by  nematodes — microscopic 
worms  which  infest  the  soil  and  which  enter  the  roots  of  tomatoes  and 
many  other  plants,  causing  a  swelling  of  the  roots  (fig.  25).  Affected 
plants  may  die  suddenly,  but  generally  appear  stunted  and  yellowed, 
and  die  slowly.  The  trouble  can  always  be  recognized  by  pulling  up 
the  plants  and  inspecting  the  roots.  Extreme  caution  should  be 
exercised  by  growers  to  prevent  the  introduction  of  the  disease  on 
vegetable  plants  or  seed  potatoes  shipped  from  other  sections.    When 


Circ.  263] 


TOMATO   PRODUCTION    IN    CALIFORNIA 


35 


once  introduced  into  the  soil,  nematodes  are  very  difficult  to  eradicate. 
Continuous  flooding  of  the  land  for  two  or  three  months,  thorough 
drying  out  of  the  soil  over  summer,  summer  fallow,  and  growing 
resistant  crops  for  two  years  are  practices  that  have  been  recom- 


Fig.  25. — Roots  of  tomato  plant  affected  by  nematodes — the  root-knot 
disease.     (From  Agr.  Exp.  Sta.  Cir.  280.) 


mended.  The  small  grains,  the  Iron  variety  of  cowpea,  and  the  velvet 
bean  are  some  of  the  crops  resistant  to  nematodes.  The  danger  of 
nematodes  is  greatest  on  sandy  soils.  One  should  always  make  sure 
that  the  soil  used  for  plant  beds  is  free  from  nematodes,  for  infected 
beds  are  often  responsible  for  infecting  the  plants  and  spreading  the 
trouble. 


36  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Mosaic. — This  disease  causes  a  mottled  and  somewhat  distorted 
appearance  of  the  leaves;  the  plants  are  stunted  and  do  not  produce 
much  fruit,  though  they  may  survive.  The  disease  is  of  the  virus 
type,  and  is  spread  in  the  field  by  insects,  especially  the  aphis,  and  by 
the  hands  of  workers  who  prune  and  tie  staked  plants.  Infected 
plants  should  be  promptly  pulled  up  and  burned  or  buried  to  prevent 
the  spread  of  infection.  Probably  the  most  important  step  in  con- 
trolling the  disease  is  to  destroy  the  perennial  weeds  related  to 
tomatoes,  on  which  the  disease  over-winters.  Horse  nettles,  ground 
cherries,  and  matrimony  vine  especially  should  be  eliminated  from 
the  neighborhood  of  the  plant  beds  and  from  the  field  as  well,  if 
possible.  The  disease  is  not  transmitted  on  the  seed,  nor  is  spraying 
effective  in  control. 

Streak. — This  disease  is  said  to  be  caused  by  double  infection  of 
the  plants  with  the  virus  of  tomato  mosaic  and  potato  mosaic.  The 
leaves  at  first  show  the  mottling  and  distortion  characteristic  of 
tomato  mosaic,  then  develop  numerous  brown  spots.  These  spots  also 
appear  on  the  tips  of  the  stems.  The  plants  are  stunted  and  die  from 
the  top  downward.  The  green  and  ripe  fruit  are  also  affected,  show- 
ing raised  greasy-brown  patches.  Streak  occasionally  occurs  almost 
everywhere  that  tomatoes  are  grown  in  California,  sometimes  in 
destructive  amounts.  It  is  most  prevalent  in  the  fall  and  winter  crop 
of  the  southern  coastal  districts.  The  control  is  the  same  as  for  mosaic. 
Tomatoes  should  not  be  grown  after  potatoes,  for  the  volunteer  potato 
plants  which  usually  are  quite  numerous  the  year  after  potatoes  are 
grown,  would  be  a  source  of  mosaic  infection  to  the  tomato  plants. 

Tomato  Yellows. — This  disease  has  in  the  past  been  referred  to  as 
summer  blight,  yellow  blight,  and  western  yellow  blight.  It  is  a  virus 
disease,  caused  by  the  same  virus  that  causes  the  curly-top  disease  in 
beets,  and  which  also  attacks  numerous  other  crop  plants  (fig.  26). 
It  is  transmitted  to  the  tomato  plants  by  the  beet  leafhopper,  a  small 
active  sucking  insect.  In  most  sections  of  California  the  yellows 
disease  does  not  occur  every  year  in  epidemic  form.  It  is  severe  only 
in  years  in  which  the  leafhoppers  are  very  numerous.  Yellows  occurs 
most  commonly  in  the  warm  interior  valleys,  where  in  some  years  the 
tomato  crop  is  wiped  out. 

Affected  plants  stop  growing,  the  leaf  margins  roll  upward,  the 
leaf  blades  become  yellowish  and  the  veins  on  the  underside  of  the 
leaf,  as  well  as  the  stems,  become  purple  (fig.  27  and  28).  The  plants 
usually  die  within  a  few  weeks  if  they  become  infected  while  young, 
while  older  plants  may  produce  a  few  inferior  fruits.  The  disease  is 
not  seed-transmitted,  nor  is  it  much  affected  by  soil  or  cultural  con- 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


37 


ditions.  Slight  shading  of  the  plants  protects  them  to  a  certain  extent, 
and  it  may  be  possible  to  combine  tomatoes  with  a  tall-growing  shade 
crop,  like  sunflowers.  Also,  thick  planting,  either  by  having  two  or 
three  plants,  in  each  hill,  or  by  having  the  plants  spaced  much  closer 
together  than  usual,  gives  some  protection.  The  excess  number  of 
plants  will  result  in  a  fair  crop,  even  though  a  high  percentage  of 
them  are  killed  by  yellows.  Late  planting  will  in  some  cases  also 
allow  the  tomatoes  to  escape  yellows.  The  Dwarf  Champion  and  other 
dwarf  varieties,  as  well  as  the  little  Red  Pear,  are  somewhat  resistant 
to  yellows. 


Fig.  26. — Proof  that  the  yellows  disease  is  carried  by  beet  leafhoppers. 
Eow  3  had  its  plants  exposed  to  infective  hoppers  for  three  days  before  trans- 
planting. Kows  2  and  4,  checks,  remained  almost  entirely  healthy.  (Courtesy 
of  H.  H.  Severin.) 

Blossom-end  Rot. — The  damage  done  by  this  disease  varies  much, 
according  to  the  season  and  soil  conditions.  The  first  stage  occurs 
on  either  green  or  ripening  fruits,  as  an  irregular  brownish  patch  at 
the  blossom-end.  If  the  trouble  does  not  develop  beyond  this  stage, 
as  is  sometimes  the  case,  little  harm  is  done.  But  generally  the 
disease  advances  rapidly,  developing  a  black  dry  leathery  rot  which 
may  advance  until  half  of  the  fruit  is  decayed  (fig.  29).  The  disease 
is  usually  associated  with  drought  conditions,  where  the  plants  are 
not  able,  on  account  of  dry  soil  or  limited  root  systems,  to  take  up 
moisture  as  fast  as  it  is  needed.  It  also  occurs  where  the  plants  have 
made  an  excessively  rank  growth  of  vines  early  in  the  season,  and  are 
then  checked  by  insufficient  moisture  when  the  fruit  is  ripening. 
Blossom-end  rot  also  often  occurs  when  tomatoes  are  grown  on  soils 
of  high  salt  concentration,  or  "alkali."  The  prevention  of  this  disease 
seems  to  lie  in  proper  regulation  of  the  moisture  supply.  The  develop- 
ment of  a  deep  root  system  by  the  plant  will  also  aid  in  preventing 
disease. 


38 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Failure  to  Set  Fruit. — This  is  a  frequent  cause  of  trouble,  especi- 
ally at  certain  seasons  of  the  year..  Although  the  plants  may  bloom 
profusely,  the  flowers  may  fall  without  setting  fruit.  One  frequent 
cause  of  the  trouble  lies  in  the  excessively  rank  vegetative  growth  of 
the  plant,  which  is  likely  to  occur  when  the  water  supply  is  too  liberal 
or  when  the  soil  is  excessively  rich  in  nitrogenous  matter.  Another 
cause  is  the  very  low  humidity  of  the  air  which  often  occurs  in 
summer.  This  condition,  in  connection  with  high  temperature  and 
high  winds,  may  cause  most  of  the  blossoms  to  fall. 


Fig.  27. — Leaves  from  tomato  plant  affected  with  tomato  yellows.  Note  the 
rolling  of  the  leaves.  This  affects  all  parts  of  the  plant.  (From  Agr.  Exp.  Sta. 
Bui.  239.) 

Avoiding  too  much  nitrogenous  fertilizer  and  irrigating  sparingly 
if  at  all  during  the  first  bloom  stage,  will  promote  a  better  set  of 
fruits.  Windbreaks  and  the  selection  of  a  type  of  plant  having  heavy 
foliage  will  be  helpful  in  other  cases. 


INSECT   PESTS 


Tobacco  Horn  Worm. — The  caterpillars  of  this  insect  are  from  two 
to  three  inches  long  when  full  grown  (larval  stage)  and  are  pale 
green  in  color.  They  are  voracious  feeders  and  defoliate  the  tops  of 
the  branches  rapidly.  They  also  attack  the  green  fruit.   The  first  brood 


Circ.  263] 


TOMATO    PRODUCTION    IN    CALIFORNIA 


39 


of  these  insects  appears  about  mid-summer;  they  rapidly  increase  in 
number  throughout  the  season.  Hand-picking  may  be  the  most 
economical  way  to  dispose  of  the  small  numbers  appearing  at  first. 
As  soon  as  they  become  numerous,  resort  should  be  had  to  spraying 
with  arsenicals.  Probably  the  most  effective  treatment  is  to  spray  the 
plants  with  arsenate  of  lead,  4  pounds  to  100  gallons  of  water.     For 


MF-J& 


r  iX*i-  ^  '  ■£«?* 


Fig.  28. — Tomato  plant  showing  advanced  stage  of  the  yellows  disease. 
(From  Agr.  Exp.  Sta.  Circ.  280.) 


small  acreages,  a  double-action  hand-pump,  mounted  on  a  sled  with 
a  50-  or  100-gallon  tank,  may  be  used.  With  a  short  lead  of  hose  and 
an  8-foot  rod,  it  is  possible  to  spray  four  rows  at  each  trip  through 
the  field.    Usually  the  spraying  has  to  be  repeated  often. 

Late  in  the  season,  when  the  plants  almost  completely  cover  the 
surface,  spraying  becomes  impracticable,  and  dusting  with  a  mixture 
of  1  pound  of  arsenate  of  lead  to  20  pounds  of  slaked  lime,  is  effective. 
Airplanes  have  been  used  to  dust  large  acreages. 


40  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Fall  or  winter  plowing  of  land  which  has  been  in  tomatoes,  will 
expose  and.  destroy  many  of  the  pupae,  thus  reducing  the  number  of 
insects  the  following  year.  They  pupate  in  the  soil  near  the  plants 
on  which  the  larvae  fed. 

Tomato  Fruit  Worm. — This  is  the  same  insect  as  the  corn  ear- 
worm.  The  larvae  are  brown-stripped  and  are  about  one  inch  long 
when  full  grown.  The  adult  moths  lay  their  eggs  on  the  foliage,  and 
the  young  larvae,  after  feeding  a  time  on  the  leaves,  bore  into  the 
green  fruit.  After  the  larvae  have  fed  within  the  fruit  for  a  time, 
the  fruit  is  made  unfit  for  market,  and  if  moist  conditions  prevail,  the 
punctured  fruits  are  often  destroyed  by  a  soft  rot.  The  tomato  fruit 
worm    is   prevalent    particularly    in    the    interior    valleys.      Control 


Fig.  29. — Tomatoes  showing  blossom-end  rot  in  different  stages  of 
development.     (From  Agr.  Exp.  Sta.  Bui.  239.) 

measures  are  crop  rotation  and  spraying  or  dusting  as  for  the  tobacco 
horn  worm.  In  fact,  the  same  program  of  treatment  will  control  both 
insects,  although  the  control  of  the  tomato  fruit  worm  will  not  be  so 
nearly  complete  as  it  is  for  the  tobacco  horn  worm.  When  spraying 
tomatoes  with  arsenicals  for  control  of  fruit  worm,  a  spreader  and 
sticker,  such  as  Kay  so,  should  be  added  to  the  spray  solution. 

Trapping  the  worms  on  corn  planted  between  the  tomatoes  has 
been  recommended,  but  this  simply  leads  to  increased  number  of 
worms  in  the  later  broods,  unless  the  corn,  with  its  worms,  is 
destroyed.  Since  the  moth  which  lays  the  eggs  of  the  fruit  worm  is 
a  night  flyer,  light-trapping  has  also  been  suggested.  However,  it  is 
found  that  the  female  moths  are  not  much  attracted  by  the  lights 
until  after  they  have  completed  their  egg  laying. 

12m-5,'28 


